RE: [PATCH rdma-core v4 4/4] ibacm: Use MONOTONIC time base to avoid timer expiration issues

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Hmm,

I don't know where my cover letter went for this patch set.

v4 cleans up the suggested type casting issues in this patch.

Thanks,
Mike

> -----Original Message-----
> From: linux-rdma-owner@xxxxxxxxxxxxxxx [mailto:linux-rdma-
> owner@xxxxxxxxxxxxxxx] On Behalf Of Michael J. Ruhl
> Sent: Wednesday, November 15, 2017 2:36 PM
> To: linux-rdma@xxxxxxxxxxxxxxx
> Subject: [PATCH rdma-core v4 4/4] ibacm: Use MONOTONIC time base to avoid
> timer expiration issues
> 
> From: Michael J. Ruhl <michael.j.ruhl@xxxxxxxxx>
> 
> The event_wait() function uses the CLOCK_REALTIME time base for
> calculating expiration times (default time base for gettimeofday()).
> 
> Using the CLOCK_REALTIME time base can introduce incorrect expiration
> timeout calculations if the REALTIME clock changes, making a timeout
> too long (possibly hours or days), or too short.
> 
> Update time base usage to the CLOCK_MONOTONIC time base to avoid time
> change issues.
> 
> Use appropriate typing to avoid unnecessary typecasting.
> 
> Reviewed-by: Mike Marciniszyn <mike.marciniszyn@xxxxxxxxx>
> Signed-off-by: Michael J. Ruhl <michael.j.ruhl@xxxxxxxxx>
> ---
>  ibacm/linux/osd.h |   22 ++++++++++++----------
>  1 files changed, 12 insertions(+), 10 deletions(-)
> 
> diff --git a/ibacm/linux/osd.h b/ibacm/linux/osd.h
> index eabf5ed..4ef7b55 100644
> --- a/ibacm/linux/osd.h
> +++ b/ibacm/linux/osd.h
> @@ -88,20 +88,23 @@ typedef struct { volatile int val; } atomic_t;
>  typedef struct { pthread_cond_t cond; pthread_mutex_t mutex; } event_t;
>  static inline void event_init(event_t *e)
>  {
> -	pthread_cond_init(&e->cond, NULL);
> +	pthread_condattr_t attr;
> +
> +	pthread_condattr_init(&attr);
> +	pthread_condattr_setclock(&attr, CLOCK_MONOTONIC);
> +	pthread_cond_init(&e->cond, &attr);
>  	pthread_mutex_init(&e->mutex, NULL);
>  }
>  #define event_signal(e)	pthread_cond_signal(&(e)->cond)
>  #define ONE_SEC_IN_NSEC  1000000000ULL
> -static inline int event_wait(event_t *e, int timeout)
> +static inline int event_wait(event_t *e, unsigned int timeout)
>  {
> -	struct timeval curtime;
>  	struct timespec wait;
>  	int ret;
> 
> -	gettimeofday(&curtime, NULL);
> -	wait.tv_sec = curtime.tv_sec + ((unsigned) timeout) / 1000;
> -	wait.tv_nsec = (curtime.tv_usec + (((unsigned) timeout) % 1000) * 1000)
> * 1000;
> +	clock_gettime(CLOCK_MONOTONIC, &wait);
> +	wait.tv_sec = wait.tv_sec + timeout / 1000;
> +	wait.tv_nsec = wait.tv_nsec + (timeout % 1000) * 1000000;
>  	if (wait.tv_nsec > ONE_SEC_IN_NSEC) {
>  		wait.tv_sec++;
>  		wait.tv_nsec -= ONE_SEC_IN_NSEC;
> @@ -114,10 +117,9 @@ static inline int event_wait(event_t *e, int timeout)
> 
>  static inline uint64_t time_stamp_us(void)
>  {
> -	struct timeval curtime;
> -	timerclear(&curtime);
> -	gettimeofday(&curtime, NULL);
> -	return (uint64_t) curtime.tv_sec * 1000000 + (uint64_t) curtime.tv_usec;
> +	struct timespec t;
> +	clock_gettime(CLOCK_MONOTONIC, &t);
> +	return (t.tv_sec * ONE_SEC_IN_NSEC + t.tv_nsec) / 1000;
>  }
> 
>  #define time_stamp_ms()  (time_stamp_us() / (uint64_t) 1000)
> 
> --
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